Method of recovering phenol from a BPA production facility and the facility for recovering the same

1. A method of recovering an unreacted phenol from a bisphenol A production facility comprising:

reacting an initial phenol and an initial acetone in the presence of a catalyst to produce a bisphenol A stream comprising the unreacted phenol of the initial phenol and a bisphenol A,

separating a purge stream comprising the unreacted phenol, and wherein the unreacted phenol is present in the purge stream in an amount of 60 to 90 wt %, based on the total weight of the purge stream;

adding the purge stream to a phenol purification section of a phenol production facility; and

purifying the purge stream in the phenol purification section to form a purified phenol outlet stream in the phenol purification section, wherein the purified phenol outlet stream comprises a total phenol concentration of greater than or equal to 99.5 wt % based on the total weight of the purified phenol outlet stream.

2. The method of claim 1 , wherein the forming the purified phenol outlet stream comprises:

heating a preheater inlet stream comprising cumene, a product phenol from the phenol production facility, and a product acetone from the phenol production facility in a preheater to form a splitter inlet stream;

separating the splitter inlet stream into a splitter top outlet stream comprising the product acetone and the cumene and a splitter bottom outlet stream comprising the product phenol in a splitter column;

separating the splitter bottom outlet stream into a crude top outlet stream comprising the product phenol and a crude bottom outlet stream comprising the cumene in a crude phenol column;

hydro-extracting the crude top outlet stream in a hydro-extractor column to form an extractor primary outlet stream comprising the product phenol; and

recovering the purified phenol outlet stream, from the extractor primary outlet stream in a finishing column;

wherein the adding the purge stream comprises adding the purge stream to one or more of the preheater inlet stream, the splitter inlet stream; the splitter bottom outlet stream; and the crude top outlet stream.

3. The method of claim 2 , further comprising purifying the splitter top outlet stream and forming an acetone product stream comprising the product acetone.

4. The method of claim 1 , wherein the separating the purge stream comprises:

crystallizing the bisphenol A in the bisphenol A stream in the presence of water to form crystals comprising one or both of crystalline bisphenol A and an adduct of bisphenol A and the unreacted phenol;

forming a crystallized stream comprising crystals;

melting the crystallized stream to form a melted stream;

filtering a solid portion comprising the crystals from the melted stream to form a filtered stream;

removing the water from the filtered stream in a water stripper to form a water stream and an unreacted phenol stream;

wherein the purge stream comprises all or a portion of the unreacted phenol stream.

5. The method of claim 4 , wherein the water is present an amount of less than or equal to 3 wt % based on the total weight of the bisphenol A stream.

6. The method of claim 4 , wherein the forming a crystallized stream comprises filtering a solid portion comprising the crystals.

7. The method of claim 4 , further comprising adding additional phenol to the crystallized stream prior to the melting.

8. The method of claim 4 , wherein the filtering the melted stream comprises filtering in a rotary vacuum filter.

9. The method of claim 1 , further comprising directing at least a portion of the purified phenol outlet stream to one or both of the bisphenol A production facility and a diphenyl carbonate production facility.

10. The method of claim 1 , further comprising:

determining an acceptable impurity level that can be present during the reacting of the initial phenol and the initial acetone;

determining an actual impurity level present in the reacting of the initial phenol and the initial acetone;

based on the acceptable impurity level and the actual impurity level, determining a recycle amount of an unreacted phenol stream to be recycled to the bisphenol A production facility and a purification amount to be directed as the purge stream to the phenol purification facility;

directing the purification amount of the purge stream to the phenol purification facility; and

directing the recycle amount to a bisphenol A reactor.

11. The method of claim 1 , wherein the purified phenol outlet stream comprises less than or equal to 0.001 wt % of each independently water, cumene, dimethylbenzyl alcohol, hydroxyacetone, α-methylstyrene, α-methylstyrene dimers, acetophenone, acetaldehyde, cumyl phenols, and phenolic resins based on the total weight of the purified phenol outlet stream.

12. The method of claim 1 , wherein the separating the purge stream comprises removing the purge stream from a storage tank prior to adding the purge stream to the phenol purification section of the phenol production facility.

13. The method of claim 12 , wherein the storage tank is in intermittent fluid communication or is in continuous fluid communication with the phenol purification section.

14. A system for recovering phenol comprising:

a phenol purification section of a phenol production facility comprising

a preheater comprising a preheater inlet and a preheater outlet,

a splitter column comprising a splitter inlet in fluid communication with the preheater outlet, a splitter top outlet, and a splitter bottom outlet,

a crude phenol column comprising a crude inlet in fluid communication with the splitter bottom outlet, a crude top outlet, and a crude bottom outlet,

a hydro-extractor column comprising an extractor inlet in fluid communication with the crude top outlet, an extractor outlet, and an extractor primary outlet, and

a finishing column comprising a finisher inlet in fluid communication with the extractor primary outlet, a product phenol outlet, and a finisher bottom outlet; and

a bisphenol A production facility comprising

a bisphenol A reactor comprising a bisphenol A reactor inlet and a bisphenol A reactor outlet;

a crystallization unit comprising a crystallization inlet and a crystallization outlet; wherein the crystallization inlet in in fluid communication with the bisphenol A reactor outlet;

a melting unit comprising a melting unit inlet and a melting unit outlet; wherein the melting unit inlet is in fluid communication with the crystallization outlet;

a filter comprising a filter inlet and a filter outlet; wherein the filter inlet is in fluid communication with the melting unit outlet; and

a water stripper comprising a filtered stream inlet, a water stream outlet, and an unreacted phenol stream outlet; wherein the filtered stream inlet is in fluid communication with the filter outlet;

wherein a purge stream comprising at least a portion of the unreacted phenol stream outlet of the bisphenol A production facility is in intermittent fluid communication or is in constant fluid communication with the phenol purification section upstream of the finishing column; and wherein the system is configured such that the purge stream exiting the unreacted phenol stream outlet comprises 60 to 90 wt % of an unreacted phenol based on the total weight of the purge stream.

15. The system of claim 14 , further comprising an ion exchanger comprising an exchanger inlet in fluid communication with the extractor primary outlet and an exchanger outlet in fluid communication with the finisher inlet and/or wherein the finisher bottom outlet is in fluid communication with the crude inlet.

16. The system of claim 14 , wherein the unreacted phenol stream outlet of the bisphenol A production facility is in fluid communication with the preheater inlet, the splitter inlet, the crude inlet, the extractor inlet, or a combination comprising at least one of the foregoing.

17. A method of recovering an unreacted phenol from a bisphenol A production facility comprising:

reacting an initial phenol and an initial acetone in the presence of a catalyst to produce a bisphenol A stream comprising the unreacted phenol of the initial phenol and a bisphenol A;

separating a purge stream comprising the unreacted phenol; wherein the unreacted phenol is present in the purge stream in an amount of 60 to 90 wt %, based on the total weight of the purge stream; wherein the separating the purge stream comprises crystallizing the bisphenol A in the bisphenol A stream in the presence of water to form crystals comprising one or both of crystalline bisphenol A and an adduct of bisphenol A and the unreacted phenol, forming a crystallized stream, melting the crystallized stream to form a melted stream, filtering the melted stream to form a filtered stream, removing the water from the filtered stream in a water stripper to form a water stream and an unreacted phenol stream, wherein the purge stream comprises all or a portion of the unreacted phenol stream;

adding the purge stream to a phenol purification section of a phenol production facility; and

forming a purified phenol outlet stream in the phenol purification section, wherein the purified phenol outlet stream comprises a total phenol concentration of greater than or equal to 99.5 wt % based on the total weight of the purified phenol outlet stream;

wherein the forming the purified phenol outlet stream comprises heating a preheater inlet stream comprising cumene, a product phenol from the phenol production facility, and a product acetone from the phenol production facility in a preheater to form a splitter inlet stream;

separating the splitter inlet stream into a splitter top outlet stream comprising the product acetone and the cumene and a splitter bottom outlet stream comprising the product phenol in a splitter column; separating the splitter bottom outlet stream into a crude top outlet stream comprising the product phenol and a crude bottom outlet stream comprising the cumene in a crude phenol column; hydro-extracting the crude top outlet stream in a hydro-extractor column to form an extractor primary outlet stream comprising the product phenol; and recovering the purified phenol outlet stream, from the extractor primary outlet stream in a finishing column;

wherein the adding the purge stream comprises adding the purge stream to one or more of the preheater inlet stream, the splitter inlet stream; the splitter bottom outlet stream; and the crude top outlet stream.